1. Field of the Invention
This invention relates to a one-way clutch used as a part for the transmission of torque, the prevention of reverse rotation, etc. such as in the driving apparatus, of an automobile, an aircraft, an industrial machine or the like. More particularly, it relates to a sprag type one-way clutch of which the number of parts and the number of manufacturing steps are reduced by an improvement in a holding method for a one-way clutch mechanism.
2. Related Background Art
In driving apparatuses, a one-way clutch interposed between an inner race and an outer race for transmitting the torque of rotation in only one direction is well known.
An assembly (or a sub-assembly excluding the outer race and the inner race) comprising the cage of the one-way clutch, a block bearing, a sprag and a quarter spring has heretofore been held by a method shown, for example, in FIG. 5 or FIG. 6 of the accompanying drawings.
The holding method according to the conventional art will hereinafter be described with reference to FIGS. 5 and 6 which are fragmentary axial cross-sectional views of a one-way clutch.
A holder 125 is of a cylindrical shape and has windows (openings) not shown, provided at equal intervals in the circumferential direction thereof and extending therethrough in radial directions, and one of the end portions of the cylinder is provided with a flange portion outwardly bent substantially at a right angle. A sprag 110 functioning as a cam for transmitting the rotational movement in one direction is fitted in at least one window, not shown, in this holder 125. At the same time, a groove is formed in the surface of the sprag 110 that contacts with an outer race 140 and an annular garter spring 170 is fitted thereinto. This garter spring 170 holds the sprags 110 on the holder 125 so that they move integrally, and it also exerts a bias necessary for meshing engagement so as to function as a clutch.
The sprags 110 are fitted into the windows of the holder 125, and an assembly comprising the sprags 110 annularly connected together by the garter spring 170 is fitted between an inner race 130 and an outer race 140.
Also, a retainer 120 is disposed on the outer race 140 so as to bear against the bent portion of the holder so that this assembly may not come apart in the axial direction thereof. Also, as shown in FIG. 6, as means for preventing the assembly from coming apart in the axial direction thereof, instead of the retainer, a snap ring 180 may be embedded in the outer race 140 so that the surface of the ring and the surface of the bent portion of the holder 125 may mutually contact with each other.
Further, in some cases, the retainer 120 bears against a thrust sliding bearing 150, whereby the positioning of the one-way clutch is completed. When the load in the thrust direction is not so great, it has often been practiced to use a spacer 160 of resin or the like also as a thrust sliding bearing. In such case, the spacer 160 of resin or the like has, for example, its resin washer lifted in and fixed to a hole formed in any partner part 150 which is a thrust sliding bearing.
In the fixing method for the conventional sprag type one-way clutch, the number of parts has become great and necessarily the number of manufacturing steps has also become great. Accordingly, the manufacturing cost has increased.